This invention relates to a fuel injection system which includes a regulator element. The invention relates, more particularly, to a fuel injection system which provides substantially continuous injection into the suction tube of a mixture-compressing, spark plug-ignited internal combustion engine, in whose suction tube there are disposed a measuring member and an arbitrarily actuatable throttle flap, one behind the other. The measuring member is pivoted in proportion to the air quantity flowing and against a normally constant resetting force which may, however, be changed in dependence on motor parameters. The measuring member actuates the movable part of a valve disposed in the fuel line for the purpose of metering a fuel quantity which is in a desired proportion to the air quantity.
Fuel injection systems of the above-mentioned type have the purpose of effecting automatically a favorable fuel-air mixture for all operational conditions of the internal combustion engine. This is done to make possible a complete combustion of the fuel and in order to avoid, or at least sharply reduce, the creation of toxic exhaust components while maintaining the highest possible performance or the least possible fuel consumption of the internal combustion engine. To achieve this purpose, the fuel quantity must be metered to the internal combustion engine very precisely according to the requirements of every operational condition of the engine. The proportionality between air quantity and fuel quantity must be changed in dependence on motor parameters such as rpm, load and temperature.
In known fuel injection systems of this type, the fuel quantity is metered as nearly as possible proportional to the air quantity streaming through the suction tube, and the ratio of the metered fuel quantity to the air quantity is changeable in dependence on motor parameters by changing the resetting force acting on the measuring member. However, in those fuel injection systems, it is possible for the measuring member to be still pivoted out of its normal position even after the ignition has been shut off and while the engine is running down; this results in additional fuel being metered and injected which can cause auto-ignition (dieseling) in sensitive internal combustion engines.